This invention relates to food snack products, and more particularly to a novel expanded potato snack having a texture and flavor closely resembling that of fresh potato chips.
Potato chips are well known snack products prepared by frying thin slices of raw, fresh potatoes. Several reasons for the commercial success of potato chips are their crisp texture and fresh potato flavor, and their suitability for mass production techniques.
Since the time potato chips first became a commercial success, food processors in this country and abroad have attempted to produce a prefabricated potato-based snack product which captures the flavor and texture of fresh potato chips, and which also has an appearance or structure similar to potato chips, and which can be manufactured in high volume at a relative low cost. Generally speaking, most prior art "expanded" potato snacks (i.e., snacks produced from a potato-based dough which is expanded to a porous condition by immersion in hot cooking oil) have not been successful commercially because they do not have the combined flavor and crisp texture resembling that of potato chips, together with the capability of being mass produced at a relatively low cost.
The prior art prefabricated potato snacks generally can be grouped in four categories which include (1) the dry collet process, (2) extrusion of dry potatoes, (3) forming a high solids content dough into a thin sheet, cutting, and frying, and (4) forming and frying potato snacks directly from a relatively moist dough.
1. In the dry collet process, a dry, thin portion of a starch-based gel, commonly termed a "collet," is expanded by a short immersion in hot fat. Typically, mixtures of potato solids and various starches are cooked to completely gelatinize all the starch molecules. The starch gels typically have a relatively high solids content, i.e., usually over 60 percent by weight. The products are held or cooled to reduce the stickiness of the gel, and are later sliced or cut into desired shapes and dried to form a hard pellet. The products are expanded to about three to six times their original thickness when immersed in hot fat. The entrapment of steam bubbles in the heated starch gel creates a uniformly porous structure when the snack is viewed in cross-section.
The processes disclosed in U.S. Pat. No. 2,863,720 to Speiser and U.S. Pat. No. 3,131,063 to Gerkens are typical dry collet processes in which dehydrated potatoes and starch at about 65% solids are gelatinized at high temperatures and pressures during extrusion, and then cut and dried to form dry stable collets.
Control of the dried collet processes, such as that of Speiser, is difficult and expensive in continuous operation primarily because of the interruptions required to allow the gels to become firm and less sticky so they can be cut or sliced and dried. The final puffed product is extremely soft in texture, there is little initial bite, and it tends to lack the flavor of fresh fried potato chips.
The potato snack product of this invention has novel structural aspects which will be described in detail below. The structure of the present snack product will be understood best by comparing it with the structure of the prior art snacks by referring to the accompanying drawings which are described in detail below. FIG. 1A is a cross-sectional elevation view showing the internal structure typical of the snacks described here in category (1).
2. In the dry extrusion process, dry starch-containing granular materials such as potato solids and corn meal are used. The moisture content of the material is normally between 12 percent to 14 percent by weight. The granular solids are fed into a single screw extruder operated at high speed and close tolerance to increase the temperature and work the granular material, thereby gelatinizing the starch in it. The material is finally forced at very high pressure through a series of die openings at the end of the screw. At this point the material expands greatly into a fluffy structured snack product due to the rapid expansion of the entrapped steam. The product is then dried to remove residual moisture and is often coated with fat. These snacks have a rather uniform porous structure with large inner voids, and a flavor quite untypical of potato chips.
FIG. 1B is a cross-sectional elevation view showing the internal structure typical of this group of potato snack products.
3. Several processes which have duplicated the appearance of fresh potato chips generally form a thin sheet of dough comprised chiefly of dehydrated potato solids and water. The dough is cut or rolled into desired shapes, normally at least partially dried, and then fried in a continuous operation to produce an expanded snack product. The dough generally has a solids range of about 60 to 70 percent by weight, and all the starch in the dough is completely gelatinized before it is fried. The pieces of partially dried dough material are generally more than 85 percent solids at the time they enter the frying medium.
Some of the products made by processes in this category are described in U.S. Pat. No. 3,539,356 to Benson, U.S. Pat. No. 3,297,450 to Loska, U.S. Pat. No. 3,451,822 to Fast el al, and U.S. Pat. No. 3,594,187 and Canadian Pat. No. 871,648 to Liepa. Generally speaking, control of the processes in this category in continuous operation is difficult and expensive, because of the requirement for complex extrusion, die cutting, and dehydration. The finished product is usually puffed to about four times it original thickness upon frying, and is characterized by uniform structure throughout the product when the product is viewed in cross-section. The texture and flavor of the fried product are generally not typical of freshly fried potato chips, and the products are difficult to store without breakage.
FIGS. 1F through 1I show cross-sectional elevation views of the internal structure typical of this group of potato snack products. 4. In contrast to the large number of prior art snacks produced by the methods in the preceding categories, attempts to make a natural tasting potato snack by forming and directly frying a relatively moist potato-based dough generally have been unsuccessful. One product formerly sold in the Western United States under the trademark Viko Chips was made by combining dehydrated potatoes and wheat flour with minor amounts of rice flour and corn flour to form a dough having a solids content of about 52 to 55 percent. The dough was extruded under high pressure through a piston extruder and fried. The texture of the fried product is relatively hard. There are no internal voids, as there is relatively little expansion during frying. (FIG. 1D is a cross-sectional elevation view showing the internal structure typical of this product.) Moreover, the flavor of the product did not resemble potato chips due to the overpowering flavor of the wheat flour.
In a similar process disclosed in British Pat. No. 1,109,930 owned by J. Bibby and Sons, Ltd., potato solids are mixed with potato starch to form a dough containing 30 to 40 percent solids. The dough is extruded through a round opening and fried. When viewed in cross-section, as shown in FIG. 1E, the fried product is seen to contain small voids filled with fat surrounded by a very thin surface skin. Essentially no expansion occurs when the product is fried. Moreover, considerable care must be exercised in frying the product because the pieces tend to stick together in the fryer.